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The Effects of Whole Body Unloading on Physiological Function

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT03195348
Recruitment Status : Completed
First Posted : June 22, 2017
Last Update Posted : October 31, 2017
Guy's and St Thomas' NHS Foundation Trust
Information provided by (Responsible Party):
King's College London

Brief Summary:
This study is a collaboration between the Centre of Human & Aerospace Physiological Sciences (CHAPS) and the Sleep and Brain Plasticity Centre (Department of Neuroimaging) at King's College London and the Sleep Disorders Centre at Guy's Hospital.The main purpose of the study is to evaluate the effects of a 7 day unloading period (simulating micro gravity) on muscle mass using three independent methods; two scanning techniques (magnetic resonance imaging (MRI) and dual x-ray absorptiometry (DXA)) and one that involves swallowing a capsule that contains a harmless chemical called creatine (D3-Creatine (D3-cr)) and then measuring its concentration in urine. In order to induce muscle loss, participants will be required to lie flat on their back on a water bed filled with water and salt (called hyper-buoyancy flotation (HBF)). As this situation is similar to that experienced in space, the investigators will also measure the effect of HBF on sleep, brain and physiological function - all things known to change in astronauts. Sixteen male subjects (18-40 yrs) will be recruited to participate in the study that will require physiological testing before, during and following both 7 days of normal conditions and 7 days of HBF bed-rest. Each subject will be exposed to the same conditions and assessments over the study period. As some loss of muscle is expected, participants will be offered an exercise rehabilitation programme upon completion of HBF with self-monitored and/or guided sessions based on those provided by the Space Medicine Office of the European Space Agency to returning astronauts.

Condition or disease Intervention/treatment Phase
Muscle Atrophy Weightlessness Sleep Disturbance Astronaut-Bone Demineralisation Syndrome Other: HBF Bed Rest Not Applicable

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 12 participants
Intervention Model: Single Group Assignment
Masking: None (Open Label)
Primary Purpose: Diagnostic
Official Title: The Effects of Whole Body Unloading on Physiological Function
Actual Study Start Date : March 29, 2017
Actual Primary Completion Date : August 30, 2017
Actual Study Completion Date : August 30, 2017

Arm Intervention/treatment
Experimental: HBF Bed Rest
7 days control period followed by a washout period, then 7 days of HBF.
Other: HBF Bed Rest
7 days of bed rest on hyper-buoyancy floatation (HBF)

Primary Outcome Measures :
  1. Whole body skeletal muscle loss [ Time Frame: 7 days ]
    The primary aim of this study is to investigate whole body skeletal muscle loss induced through 7 consecutive days of HBF using three independent methods; dual x-ray absorptiometry (DXA), magnetic resonance imaging (MRI) and D3-Creatine dilution (D3-cr)

Secondary Outcome Measures :
  1. Regional differences in muscle loss [ Time Frame: 7 days ]
    Regional (upper v lower limb) differences in muscle atrophy induced by HBF

  2. Relationship between change in total skeletal muscle mass and rectus femoris cross sectional area [ Time Frame: 7 days ]
    To determine the relationship between change in total skeletal muscle mass (measured by MRI) and change in physiological cross sectional area (PCSA) of the rectus femoris as determined by ultrasound measurements of fascicle length and pennation angle.

  3. Central nervous system changes induced by 7-day HBF [ Time Frame: 7 days ]
    To use neuroimaging, polysomnography and cognitive battery to investigate any structural (MR brain), neurophysiological (PSG/EEG) and functional (rs-fMRI and CANTAB battery test) central nervous system changes induced by the intervention

  4. Myofiber cross-sectional area changes with unloading compared with quadriceps cross sectional area [ Time Frame: 7 days ]
    To determine the change in single muscle fibre cross-sectional area, using immunohistochemical staining, compared to total quadriceps cross-sectional area using ultrasound. Myofiber cross-sectional area will be measured using muscle biopsy tissue which will be mounted onto cork and cut into 5 μm-thick cryosections. Immunohistochemical stainings of muscle tissue cross sections will then measured using a microscope.

  5. Muscle biochemistry [ Time Frame: 7 days ]
    To determine the change in biochemical (protein:DNA ratio) markers of quadriceps size in relation to the MRI and ultrasound measurements

  6. Change in fractional protein synthesis [ Time Frame: 7 days ]
    To determine the relationship between change in quadriceps skeletal muscle mass (measured by MRI) and change in fractional protein synthesis (FPS) rate measured using tracer (D2O) techniques

  7. Changes in anabolic and catabolic signalling markers in muscle [ Time Frame: 7 days ]
    To investigate changes of anabolic and catabolic signalling markers (such as MAFbx/atrogin-1 and MuRF1) in quadriceps muscle after 7 days HBF

  8. Changes in muscle function [ Time Frame: 7 days ]
    To measure changes in muscle function as a result of 7 days HBF. These will include maximal voluntary isometric strength of the knee extensors, plantar flexors in the trunk and hand (hand grip) and explosive power during a countermovement jump.

  9. Changes in cardiorespiratory fitness [ Time Frame: 7 days ]
    To measure changes in cardio respiratory fitness (maximal aerobic capacity (VO2max)) with 7 days of immobilisation

  10. Bone mineral density [ Time Frame: 7 days ]
    To measure changes in bone mineral density (BMD) of before and after a 7 days HBF

  11. Plantarflexion strength [ Time Frame: 7 days ]
    To determine the effect of 7 day HBF upon plantar flexion power output using an isokinetic dynamometer

  12. Muscle tone [ Time Frame: 7 days ]
    To determine the effect of 7-day HBF upon the viscoelastic properties of superficial muscles and the Achilles tendon using Myoton.The viscoelastic properties of relaxed arm flexor, arm extensor, erector spinae, lateral gastrocnemius and Achilles tendon will be determined at rest (HBF) using the Myoton (hand-held myometer) on day 1, day 3, day 5 and day 7 (last day) of the HBF. This will be done by applying a short (15ms) and almost imperceptible mechanical impulse (force 0.4N) applied directly to the skin. The following parameters are derived from the oscillation acceleration signal generated by the mechanical impulse in real time by the Myoton's software: 1) Dynamic stiffness: which indicates the resistance to deformation of a tissue, 2) Oscillation frequency: which indicates the (muscle) tone or intrinsic tension of a tissue, 3) The logarithmic decrement of the oscillation: which characterises tissue elasticity.

  13. Functional re-adaptive exercise device (FRED) [ Time Frame: 7 days ]
    To determine the ability, utility and potential efficacy of FRED following 7 days HBF

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years to 40 Years   (Adult)
Sexes Eligible for Study:   Male
Gender Based Eligibility:   Yes
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • Males aged 18-40
  • No clinically significant and relevant abnormalities in medical history
  • Absence of any condition that could affect subject safety or well-being or their ability to understand and follow study procedures and requirements
  • Absence of any condition which has/will result in irregular regulation of skeletal muscle, creatine metabolism or reduction of total skeletal muscle mass
  • Absence of a medical history that includes back pain

Exclusion Criteria:

  • Known or suspected intolerance or hypersensitivity to the study materials (or closely related compounds) or any of their stated ingredients
  • Habitual use (>twice a week) of creatine supplementation within 6 weeks of the study
  • Previous history of smoking
  • No known current or past neurological or psychiatric co-morbidities, no known sleep abnormalities (e.g. insomnia, snoring, sleep apnoea, sleep-walking/talking, nocturnal panic attacks, restless leg syndrome)
  • Participation in another clinical study or receipt of an investigational drug within 30 days of the screening visit
  • Relation of any study investigators, personnel at the study site or employee of any of the study sponsors
  • Any kind of medication prior to 1 month of screening
  • Recent history (within the last 1 year) of alcohol or other substance abuse
  • A previous history of nosebleeds

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT03195348

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United Kingdom
Sleep Disorders Centre
London, United Kingdom
Sponsors and Collaborators
King's College London
Guy's and St Thomas' NHS Foundation Trust
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Principal Investigator: Ivana Rosenzweig, PhD King's College London

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Responsible Party: King's College London Identifier: NCT03195348     History of Changes
Other Study ID Numbers: 206237
First Posted: June 22, 2017    Key Record Dates
Last Update Posted: October 31, 2017
Last Verified: October 2017
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: No

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Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No
Additional relevant MeSH terms:
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Bone Demineralization, Pathologic
Sleep Wake Disorders
Muscular Atrophy
Pathological Conditions, Anatomical
Nervous System Diseases
Mental Disorders
Neurologic Manifestations
Signs and Symptoms
Neuromuscular Manifestations
Bone Diseases, Metabolic
Bone Diseases
Musculoskeletal Diseases
Metabolic Diseases